1. Field of the Invention
This invention relates, in general to photocopying and, more specifically, to an apparatus for cleaning toner from surfaces in hardcopy producing apparatus.
2. Description of the Prior Art
Printers, copiers, duplicators, and like devices which use a photosensitive member to develop and transfer an image ultimately to a hardcopy output medium, such as a sheet of paper or transparency, can operate in several different modes. An intermediate transfer step is used in some apparatus to transfer the images from the photosensitive member to the paper. In this type of apparatus, the image is first transferred to an intermediate roller, drum, or belt, and then transferred from that member to the paper. When color images are being produced by the intermediate process, the traditional method is to register all of the individual color component images on the intermediate transfer device to form the composite or final color image before transfer to the paper.
Most types of photocopying devices developed the latent images with toner, often in the form of a dry power. Inherent in the process is the need to remove or clean residual toner and carrier from the photosensitive member at various stages, including after the majority of the toner in the developed image has been transferred. In devices with intermediate transfer members, it is desirable to clean toner from both the photosensitive member and the intermediate transfer member.
Customer maintained printers, copiers, and like devices using the electrophotographic process require periodic toner replacement and disposal under normal operating procedures. In order to make such procedures as simple and foolproof as possible, the number and frequency of such operations should be held to a minimum. This includes the number of containers to empty or replace. According to the prior art, some customer maintainable devices achieve this result by combining more than one customer maintainable function into a single replaceable device or cartridge. For example, the toner supply, the cleaned toner reservoir or sump, and the photosensitive member can all be contained in a single removable housing which is removed and replaced with a new one when the toner needs replenished. This eliminates the need for a separate device for removing toner and carrier cleaned from the photosensitive member assuming, of course, that the toner sump is correctly sized to hold all reasonable amounts of cleaned toner without overflow before the cartridge needs replacing because of a lack of unused toner in the cartridge. U.S. Pat. No. 4,750,015, issued on June 7, 1988, teaches a modified version of the above-described approach. In this patent, the photosensitive member and the collected toner container are housed in the same structure which can be removed and replaced. The toner supply is contained in a different structure.
Several U.S. patents describe or teach cleaning systems with various forms of excess toner collection. U.S. Pat. No. 4,767,689, issued on Aug. 30, 1988, shows a fluid development system which collects in a common sump the excess toner from both a developing station and a cleaning station. The developer apparatus, cleaning apparatus, and toner sump are all contained within the same housing, as shown in FIG. 7 of the patent.
U.S. Pat. No. 4,252,433, issued on Feb. 24, 1981, shows a cleaning system for removing toner from an electrostatic recording member. A roll member cooperates with a blade member to form a single cleaning station which removes, collects, and discharges toner through a conduit. U.S. Pat. No. 4,618,250, issued on Oct. 21, 1986, shows a cleaning system which uses a form of a rotating magnetic roller cleaner, which basic principle is used in part of the cleaning system of the present invention.
U.S. Pat. No. 4,030,824, issued on June 21, 1977, shows a guide or conduit member arranged to discharge toner, collected by one cleaning station, to a remotely located sump. A special valve is illustrated for closing the conduit when the cleaning station and the sump are separated when the reproducing apparatus is opened. U.S. Pat. No. 4,724,459, issued on Feb. 9, 1988 to the same assignee as the present invention, shows the use of a vacuum system for removing collected toner particles from the cleaning apparatus and transporting them to another area for reuse or disposal.
Therefore, as discussed herein, it is desirable and an object of this invention, to provide a cleaning system for electrophotographic apparatus which is easily maintained by the operator. It is also an object of this invention to provide a cleaning system which keeps operator maintenance to a minimum in apparatus which includes an intermediate transfer member from which toner is cleaned.